"Let's go! The rats are beatable, we can clear this portion of the raid instance!" The temporary Pandaren leader shouted and everyone was encouraged to do it since they could see that they were progressing.
However, as they were pushing forward to get full control of the third layer, they suddenly felt the ground shaking. All of them did not care about it since the explosions from the missiles and other cultivators' spells had always been this earth shattering but when they realised that the ground was shaking nonstop, they started to become suspicious.
Some of the Pandarens, especially the Pandawans on the ground, who had more battle experience, could feel that this might not be an ordinary earthquake spell and began to move to higher grounds like the ruins of the second layer.